


Stacy's Mutation

by Skullossal



Category: Original Work
Genre: Breast Expansion, F/M, Giantess - Freeform, Growth, POV Male Character, POV Second Person, Size Difference, Size Kink, expansion, hourglass - Freeform, huge boobs
Language: English
Status: Completed
Published: 2021-02-10
Updated: 2021-02-10
Packaged: 2021-03-16 23:20:06
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,115
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29340450
Author URL: https://archiveofourown.org/users/Skullossal/pseuds/Skullossal
Summary: Stacy's rare mutation is the cause of some growing concerns.
Kudos: 8





	Stacy's Mutation

[Contains: Giantess Growth, Breast Expansion, & Size Play]

“Keep going! I’m almost there!” Stacy moaned.

Your fingers dug into the mattress. Two amazonian hands pinned your forearms to the bed; a pair of thick thighs braced around your waist. Your member twitched, surrounded by a hot prison of ceaseless pleasure. Stacy pressed her advantage.

For the third time tonight, you attempted to hold on a little longer. It was futile. Stacy’s gentle command of your limbs tightened. ‘Relax honey,’ signaled her grip, ‘you wouldn’t want me to get rough, would you?’. Exhaustion set in, bringing with it an end to your struggling. Stacy’s domineering grasp loosened. But only just a little.

You found yourself once again reviewing how this sexual crucible began. Really, how many guys had 6’8” girlfriends? A lucky handful existed, to be sure. But few of those women were stacked to kingdom come. Even less could match Stacy’s raw strength and boundless stamina. Still, the ultimate question echoed in your mind: ‘How long was she going to keep growing?’

You first met only a few months ago. Stacy’s personality matched her figure at the time. She was small, shy, and rather unnoticeable: The kind of girl that faded into the background when you looked around the room. It was why you were caught off guard when she approached you. The tiny girl stuttered as she confessed that -you- were the subject of her massive crush; It was flattering, to be honest. You decided to ask her out.

Your first dates of heavy petting gradually built up to cautious grinding. You made the slow round of the bases together, leading a shy Stacy towards home plate. And the night you crossed it; well… that’s when things changed.

To your surprise, Stacy initiated sex again just a few days later. Then, she arranged for a steamy double-header the day after that. You happily went along for the ride. The sex increased in frequency until it was a daily routine. Then you noticed it. 5’2” Stacy didn’t look so 5’2” anymore.

Of course, she laughed off your questions, reassuring you that her boobs weren’t bigger, and she certainly wasn’t taller. You were just imagining things, darling.

‘You’re just imagining things,’ lasted for about a week. Then she had to buy new clothes. Her answers changed, becoming: ‘These are just new heels’, or ‘It’s called a padded bra’. 

Nevermind the fact that her eye-line loomed a little closer to yours with each passing day, or that you could no longer cup her ballooning tits within your palms.

After every round of sex, Stacy walked with more confidence. A charismatic aura of relaxed self-assuredness followed her wherever she went. Her nervous quirks faded. She became more outspoken, more assertive. Soon her hand wrapped around your waist in public. She even spoke for you; and why not? She always knew what to say. You found yourself going along with it all despite yourself; It was a bit of a turn on, to be honest.

Even so, Stacy’s growth became undeniably obvious. A month of casual flings later, and she matched you in height. Yet with her… proportions and her possessive nature, Stacy’s presence felt far larger. Eventually, her excuses ceased.

It was then she informed you about her rare ‘condition’: A strange mutation in the form of a hyperactive pituitary gland; It activated only under extreme arousal, causing a cocktail of growth hormones to flood her system. Masturbating rarely did anything, Stacy admitted. But when she was with you, well, the effect increased considerably.

‘So yes, darling, I’m taller than you now.’ She finally answered. ‘So what?’.

You told her you had no complaints. Stacy smiled at your response. Then she asked, no-- commanded you to move in with her.

When you mentioned you couldn’t afford the rent. Stacy waved it off. “You’ll just pay me in sex.” She declared. You laughed then, even after you realized it wasn’t a joke. Free sex and free rent? Your signature graced the lease later that same night. It seemed like the easiest decision of your life.

Each morning you woke up to a woman covering more of the bed beside you. She began ‘borrowing’ your sweaters, only to apologize later when they returned stretched out. Her dinner portions made yours look like kiddie meals in comparison. She managed to out-drink you with ease and tuck you into bed after the fact. (After squaring up your debt, of course).

The only problem? Sex had no exchange rate. Stacy’s growing libido determined the market, and the price grew steeper with each passing day. After a few days, a single session of lovemaking no longer sated her lust. Soon, your girlfriend bounced on your weary cock morning and night. A week later, and even thrice a day wasn’t enough.

Days began to stretch outwards into a smothering blur of sex.

Your crotch constantly ached; more weight shed off with each passing day; a haze of unending fatigue made even simple actions difficult. You were in over your head.

A forceful hump shook your frame, returning you to the present. The woman riding you cowgirl-style smirked. More piledriving humps rained down, milking your cock for all it was worth.

Stacy’s toned arms now surpassed yours in length. Hypnotic G-cup breasts jiggled to-and-fro. The twin headlights of her nipples rolled in lewd, bouncing ellipses. Below them her thick frame sloped inwards at the waist, forming the soft ‘V’ of a toned midriff. Further down, 

Stacy’s curves arced outwards once again: Your girlfriend’s panoramic hips flared wide, stretching an undersized pair of panties to their engineered limit.

“Just- relax- darling-.” Stacy panted. A line of sweat dripped down her navel. She was close. You shuddered, hanging on the brink of orgasm. Stacy thrust downwards, forcing you deeper inside her. She flashed a knowing smile, and received a reward for her efforts: You came, releasing a ball-aching series of spurts. The mind-numbing climax continued as the velvet walls around your cock squeezed tighter, milking you for every last drop.

Stacy sighed, rolling her eyes upwards as she joined in on the orgasm. The shuddering tremors of her coitus rocked your body with the force of a jackhammer. Together you moaned in sync, lost in the steamy limbo of sweat and arousal. Her climax stretched out, lasting long after yours. After a few minutes, the bed-rocking tremors gradually faded.

“Good job, darling.” Stacy finally sighed. She relinquished your forearms.

“Glad- I could- help.” You gasped.

Stacy didn’t respond. Her cool eyes looked lost and out of focus.

You gulped: You knew that look. It was coming.

The vise-like grip around your cock faded as Stacy lifted herself off your crotch. She shivered and hugged her arms together. The spring mattress squealed. Stacy’s figure gained mass: her hips swelled wider, sliding a pair of pink panties down her legs. Her labia drooled with obscene excitement, flush with pheromones and the musk of arousal.

Not to be outdone, Stacy’s sturdy thighs padded out thicker. A waistband of pink elastic stretched around two muscular quads, each now rivaling the girth of your chest. The doomed panties trembled. Stacy flexed, sending them fluttering to the bed in tatters with a satisfying snap of elastic.

Your eyes drifted upwards, just in time to witness Stacy’s bust inflate. Her chest filled out in a pulsing series of jiggles. Underboob spilled forth in a swell of sweat, unable to be contained. Soon a wall of cleavage overwhelmed her locked forearms. Stacy let go, sending heifer-worthy JJ-cup breasts crashing outwards: The head-smothering expanse wobbled above you like pillowy wrecking balls.

“Fuck…” Stacy gazed down at her hyper-voluptuous physique. Exploring hands brushed against the engorged curves of her endowments. A glimmer of perverse pride twinkled in her eyes.

Your girlfriend rose a few inches taller. Then she grew a few inches more. You gawked up at the growing woman above you: This growth spurt surpassed anything you ever witnessed previously.

“Ooh! This is different.” Stacy exclaimed. “My mutation is seriously kicking in this time, huh?” Her towering figure crossed the threshold of seven feet. “It’s almost like…” She trailed off. 

The growth began to slow.

The room fell silent for a moment. You used the lull to search in vain for a nearby glass of water, or perhaps an ice-pack for your sore groin. No dice.

Your eyes returned to Stacy. The small giantess that was your girlfriend seemed oddly quiet. Her brow furrowed in concentration.

“Is everything…. Ok?” came your voice. Did you always sound this timid?

“I think I feel something,” Stacy answered. “I couldn’t before… maybe I was too small to notice. But now-” The seven-foot woman shuddered...

Then her navel inched another few inches higher.

“I feel so fucking horny.” 7’3” Stacy continued.

The bed groaned.

Stacy kept rising.

“I could never control my growth.” She explained, passing 7’5”. “But it’s like I flipped a switch, y’know?”

Her eyes gazed downwards, looking for confirmation.

You did your best to nod as if you knew what the 7’7” amazon meant.

“Now it’s like using a muscle.” Stacy leaned back. She gave her legs an idle flex. Your crotch once again submerged beneath the sweaty embrace of two muscular thighs. A powerful derriere wobbled atop your quads. Another large spurt of growth pushed Stacy over eight feet in height.

The evolving giantess gave the ceiling a casual pat. “I think I could just keep going…” She murmured.

“Keep… going?” You squeaked, now weighed down by a titanic mass of ass.

“Like I don’t need to stop.” Your girlfriend explained. “I’m just getting hornier.” The bed groaned. “And bigger,” Stacy groaned as well.

Her JJ-cup bust enlarged once more. Twin mountains bulged forth, separated only by a vast valley of cleavage. Her hips widened, expanding into door-destroying love-handles. Stacy’s lewd shadow swallowed the bed. Her head bent downwards to fit the room. A hand the size of your torso enveloped your chest. Fingers, each more powerful than your entire arm, locked tight around your shoulders.

“I think I’m just gonna keep going.” Stacy’s voice betrayed no hint of self-doubt. Her shoulders sloped against the top of the room. Cracks formed in the plaster above. Was she 12 feet tall now? 15 feet? You couldn’t say; her growth wasn’t stopping.

With a controlled fraction of her strength, Stacy lifted you off the bed. Your legs dangled in mid-air like a limp marionette. “The sex was great babe,” Your girlfriend apologized. “But I think we’re past that point.” With that, she opened her hand and let you go. Suddenly you were falling, tumbling downwards in a whirl of surprised limbs.

A soft waterbed cushioned your landing. You blinked, resting atop the immense pillows of Stacy’s breasts. “Um. Listen,” You began, trying to sit up. Two mischievous eyes loomed above you. “M-maybe we could just talk abou-”

A lone finger interrupted your speech. It gave your torso a gentle prod. The room faded from sight as you sank downwards. A warm prison of boob overwhelmed your vision. Stacy tucked you deeper into her immobilizing cleavage.

“Why don’t you just enjoy the ride?” Her faint voice sounded from above.

You tried to climb up, back towards the light; back towards freedom. A few seconds of futile struggling only sent you further into the buxom abyss. It was no use: an endless reservoir of bust trapped you better than any quicksand could.

There was a muffled crash as Stacy outgrew the room. “Ah, that’s better,” came a giggle from above. “Now hun,” her voice continued, “let’s make sure you never need to worry about falling out.” A sloshing sound surrounded you. “How about I grow my breasts some more?”

The walls of cleavage pressed tighter. Stacy’s breasts engorged, evidently doubling in size. A portion of the hot, smothering expanse bulged up beneath your groin, forcing your cock outwards: It grew stiff despite your exhaustion.

Supple, jiggling flesh now filled the pocket of space surrounding your member. A relentless pressure squeezed it on all sides; each quake of Stacy’s colossal breasts massaged your length, edging you further. Soon the sensations grew too great to bear: You erupted into the throes of a bucking orgasm, coating a canyon of cleavage with your seed.

“Aw, You came?” Stacy’s muffled voice teased from somewhere up above. “And just from my tits? How cute!” The dull vibration of heavy footsteps echoed off from far below. “I wish you could see the view,” She continued. “Downtown looks great from up here!”

Exhaustion set in: You drifted away, lost in post-orgasm bliss. Stacy’s voice faded into the void. Sleep overcame you, and with it, dreams of large women.

Fin.


End file.
